Plastic bags are well known in the art. Such bags may be used for containing a variety of items. A popular use for plastic bags is to contain and display food items such as poultry and the like. Exemplary of the prior art are the following patents:
U.S. Pat. No. 5,116,140 discloses an easy-to-open synthetic resin bag including (a) a bag body substantially composed of a pair of laminated walls made of synthetic resin films, the peripheries of the laminated walls being heat-sealed to form a sealed border region while defining an unsealed storing space within the sealed border region, (b) a tear string which is heat sealed along an imaginary opening line on the inside of one of the laminated walls, the tear string having both ends thereof heat sealed in a sandwiched condition on the corresponding portion of the sealed border region, (c) a pulling tab formed by cutting a part of one side portion of the sealed border region which corresponds to one end of the tear string, the pulling tab being tearable from the bag body integrally with the tear string, and (d) a tear string retaining portion including a transverse opening which is formed by cutting off a part of the other side portion of the sealed border region and a pair of inside and outside heat sealed portions which are located at both sides of the transverse opening, the transverse opening extending in a direction perpendicular to the tear string such that the tear string passes through a central portion of the transverse opening. Due to such a tear string, retaining portion, the separation and complete removal of the tear string from the bag is reliably prevented while assuring the easy bag opening operation.
U.S. Pat. No. 5,050,736 discloses a reclosable package including interlocking closure strips positioned outside of a hermetic seal or seal area and the method for producing same. The hermetic seal is of the easy-open or peelaway type so as to not destroy the integrity of the package or closure strips upon opening of the package.
U.S. Pat. No. 5,036,543 discloses a form, fill, seal and separate packaging machine for reclosable containers to web by a plurality of stations disposed along a path of travel of a thermoplastic web including a device to attach a pair of mated, resealable closure strips to the base web. The machine is intermittent in its operation, with movement of the web through the machine controlled so that the various steps of applying the closure strips, forming, filling, sealing and separating the reclosable containers are performed during periodic stops of the machine. The machine is further characterized by its use of two pairs of web belts to move the web through the machine. A first pair of web belts initially receive the folded web stock and partially form and completely fill the containers. The second pair of web belts overlap with the downstream end of the first pair of belts, but are disposed lower than the first belts. When the filled partially formed containers pass from the first pair of belts to the second pair of belts, the unsealed free ends are exposed for final sealing and severing.
U.S. Pat. No. 5,022,530 discloses a modified zipper elements for easy open containers having interlocking zipper elements and a tear strip for opening the container along the upper edge, wherein the bases of the zipper elements are extended upward towards the tear strip to limit the area of tearing and protect the zipper elements, and a method for making.
U.S. Pat. No. 4,909,017 discloses a reclosable bag material, method and apparatus which is a new method of making a form fill bag having a reclosable fastener thereon and a mechanism therefor wherein a continuous length of film is advanced and joined first and second fastener profile strips are laid laterally onto the film of a length substantially equal to one-half of the film width, the film is advanced and formed into a tube with the side edges folded together and seamed, the first profile strip is attached to the surface of the film prior to forming it into the tube and the second opposed interlocked profile strip is attached to the inner surface of the film after it is formed into a tube, and a cross-seam is formed in the tube above the closure strip to form the bottom of the succeeding bag, and a completed bag is cut from the film by cutting below the bottom seam and above the fastener strips.
U.S. Pat. No. 4,894,975 discloses a method and apparatus for making reclosable bags with fastener strips in a form fill and seal machine from a supply of thin thermoplastic film with the film being formed into tubular shape about a filling tube with the edges of the film brought together and joined solely by a zipper strip having reclosable pressure interlocking members thereon with the zipper strip preferably heat sealed to the film and the zipper strip having a web between the pressure interlocking members which provides a tamper-evident juncture between the edges of the film so that the web must be severed for access to the interior of a bag formed from the film, and individual bags formed from the continuous tube by filing the tube through the filling tube and cross-seaming and cutting individual bags from the continuous film tube.
U.S. Pat. No. 4,782,951 discloses a reclosable package and method of making reclosable package including interlocking closure strips positioned outside of a hermetic seal or seal area and the method for producing same. The hermetic seal is of the easy-open or peelaway type so as to not destroy the integrity of the package or closure strips upon opening of the package.
U.S. Pat. No. 4,617,683 disclosed a reclosable bag, material, and method of and a device for making same wherein in one aspect extruded resiliently flexible plastic profiled reclosable fastener strip device for reclosable bags is located across the longitudinal formation axis of the bag wall web material, and in another aspect of the invention single strip fastener strip has at one or more suitable locations there along separations across the profiles, such as notches, to facilitate bending or folding of the strip upon itself so that the self-interlocking profiles of the portions of the strip folded upon themselves are adapted for reclosable interlocking with one another. The interlockable portions of the strip may have separable air tight sealing ribs therealong. The web and fastener material and fastener assembly is especially suitable for machines wherein the bags are formed, filled and sealed.
U.S. Pat. No. 4,241,865 discloses a reclosable shipping sack and method, the sack having a pouring mouth from which discrete pourable contents may be discharged, including a primary non-reclosable stitched closure fastener across and closing the mouth against unintentional discharge o the contents and including a device such as chain stitch and rip strip for facilitating digital opening of the primary closure fastener. A secondary, reclosable fastener, desirably of the zipper type, extends across the sack mouth outwardly from the primary closure fastener and is adapted for selectively opening and closing the sack mouth after opening of the primary closure fastener. A method of making the reclosable sack is also disclosed.
U.S. Pat. No. 3,473,589 discloses a plastic bag having a closure structure and a method for making same, the structure having a first thin inner layer of flexible plastic material with a first fastener element extending therealong formed of a resilient material and being of one piece with the layer, a second thin layer of flexibly plastic material facing the first layer and having a uniform second fastener element extending therealong formed of a resilient material and being of one piece with the second layer and shaped to be releasably interlocked with the first fastener element, a first outer layer positioned over the outer surface of the first inner layer and laminated thereto, the first inner and outer layers providing a first substantially monolithic wall so that the first inner layer provides a support with the layers coacting and allowing a stronger lock with a thin film, and a second outer layer positioned over the outer surface of the second inner layer and laminated thereto, the second inner and outer layers providing a second substantially monolithic wall so that the second inner layer provides a backing for the support allowing a stronger lock with a thin film, the outer layers laminated to the inner layer opposite fastener elements so as to reinforce the inner layers in the area of the fastener elements.